A4000TX ATX Amiga motherboard
 

Let me introduce to you the latest Amiga motherboard project I've been working on.

A4000TX ATX motherboard, the first Amiga based motherboard in ATX form factor (actually a hybrid ATX/EATX form factor).
A4000TX is an A4000cr motherboard and daughterboard embedded together with a few additional features.
The motherboard is fully hand-routed like the A4000+ Alice motherboard was.

The specifications of the A4000TX Lisa rev 1.0:
- fits into (E)ATX case
- uses standard ATX power supply
- Amiga AGA custom chipset
- CPU slot connector for accelerator cards
- on-board 68030 CPU
- on-board 68882 FPU
- 16 MB Fast RAM
- 2 MB Chip RAM
- four full-length Zorro III slots
- three ISA slots
- extended video slot
- 3.5" IDE port
- internal floppy port
- PS/2 keyboard port supporting Amiga and PC keyboards (PC work in progress)
- PS/2 mouse port (work in progress)
- Amiga mouse and joystick ports
- serial and parallel ports
- 15-pin VGA port with 15kHz RGB output
- 24-pin breakout header with full RGB port support (for external scandoublers, genlocks, SCART cables, etc..)
- 3.5mm stereo jack
- on-board RTC with battery

Blank PCB

Here are pictures of the blank pcb.
https://thumbs2.imgbox.com/2d/da/LI0QeDkJ_t.jpg https://thumbs2.imgbox.com/64/b2/1SEG7NsH_t.jpg

The board is a four-layer PCB, which is quite crowded with components and traces both on the top and bottom side.
There is no space left on the board for many additional components.

Assembled PCB

Here are a few pictures of the assembled PCB.
https://thumbs2.imgbox.com/f1/83/tf0RI3pn_t.jpg https://thumbs2.imgbox.com/c6/5e/ch22OTJU_t.jpg https://thumbs2.imgbox.com/43/2d/LbDiH8CG_t.jpg
https://thumbs2.imgbox.com/1c/e6/iEynzO1N_t.jpg https://thumbs2.imgbox.com/09/f3/Ev4ZbD0K_t.jpg https://thumbs2.imgbox.com/3d/c7/afxHHUzX_t.jpg
https://thumbs2.imgbox.com/cf/66/frLrmESG_t.jpg

Motherboard installed in an ATX case

The motherboard was installed in a standard ATX case.
https://thumbs2.imgbox.com/7e/5c/pNNX9Lcg_t.jpg https://thumbs2.imgbox.com/eb/97/kauqWZNe_t.jpg https://thumbs2.imgbox.com/97/08/XPqE6wpu_t.jpg
https://thumbs2.imgbox.com/bf/67/9ejL1eZh_t.jpg https://thumbs2.imgbox.com/86/42/dllSMZlc_t.jpg https://thumbs2.imgbox.com/5d/4b/e8dtXtP1_t.jpg

Motherboard I/O connectors

Here is a picture of the back of the case showing the I/O connectors.
https://thumbs2.imgbox.com/03/c7/kqvIpzfD_t.jpg

I/O connectors from top left to bottom right are
- PS/2 keyboard (Amiga or PC)
- PS/2 mouse (PC)
- Amiga mouse port
- Amiga joystick port
- serial port
- parallel port
- VGA port (15kHz RGB output)
- 3.5mm stereo jack

Behind the VGA port is the 24-pin breakout header to which you can plug in your custom-made cable (for scandoublers, genlocks, SCART, ...).

A4000TX motherboard dimensions

The picture below shows how much free space is required at the bottom of the case for fitting the motherboard.
https://thumbs2.imgbox.com/7f/9b/6sgsvlWJ_t.jpg

The A4000TX motherboard is a hybrid ATX / EATX form factor board.
The standard ATX motherboard dimensions are 30.5cm x 24.4cm, EATX has 30.5cm x 33.0cm (height x width) (EATX = Extended ATX).

The aim was to create an Amiga motherboard that would fit to most ATX cases and still support full-length Zorro cards.
Top side of the motherboard has standard ATX dimensions (24.4 cm wide).
The bottom side had to be made wider (30 cm) so that full-length Zorro cards can be used with the motherboard.
The motherboard can be fitted into a standard ATX case if there is enough space at the bottom of the case. A full-length Zorro card is 34cm long.
Alternatively the motherboard can be fitted into an EATX case.

In the picture the motherboard was installed into an Enlight ATX case that takes standard size ATX motherboards only, no EATX.
And yet the motherboard fitted in well.

Epilogue
The motherboard is fully working (except the PC keyboard and PC mouse support that need fine tuning).

I have some prototype boards that I will be putting for sale soon if there is interest.

I would like to hear what you think, is there a demand for an ATX motherboard like this.
And also if there are some features missing that you would like to have in some later revision (reasonable please, can't embed a PPC there...).

All kind of discussion is welcome. Thanks.

Congratulations !

Very good project !

VERY cool!
Slightly off topic but are there plans for a CPU slot to Vampire adaptor( either from the vampire devs or anyone else)
Is it about time we got some cash together and got that wonderfull Mr Haynie to make a new Buster to grace this (and other A4000`s)
Maybe we could get him to think about a serialiser/deserialiser and bring us into a more modern age... sorry going very off-topic

Again, VERY cool project and I wish you all the best

Megacool, been waiting for this!

Would be cool if you could enable the use of PC floppy drive, and footprint for pin-headers behind every DSUB for the option to relocate the DSUBs would also be nice.

Tremendous!

Very cool! Would a version with PCI slots instead of ISA slots be doable, where you plugin your mediator bridge board or is the mediator daughter board too different from the standard A4000 one?

Oh and some usb sockets would be good somewhere with the DB9/Keybaord/Mouse etc., saves a bracket.

This is so cool! Good work

Awesome! =)

0. GREAT JOB!

1. I would like to ask if the MC68030 have to be populated in case there will be cyberstorm in the cpu slot.

2. PS2 mouse and keyboard is nice but USB ports would be much better. Even fake usb for mouse only instead of ps2 would be nice improvement...

Brilliant!

Hey why don't you add a PP... oh nevermind. I wonder is there enough room to fit one of these: http://elbox.com/products/mediator_pci_3_4000t.html
Great work!

It's worth a try. :D

Just amazing.

holly cow... lol congratz for amazing work mate.

about the sugestions for elbox pci etc, why not use the available Prometheus project ( http://krashan.ppa.pl/articles/prometheus/ )?

also might not be important for others but is possible to connect more than 2 FDD using a special cable? the rest is perfect :)

Very interesting project, where did you find the connectors for the Risers for Ser/Parallel and Dual 9 Pin Din (Mouse/Joystick)?

I mean it looks like it might fit, screw holes for mounting posts are probably not going to line up. But otherwise I guess it would work.

This is outstanding work hese. Thank you, keep it up! :lol

Looks fantastic!

I wish it was possible to get something like that fully populated as I have no components...

Very cool. Amazing work. I do really like it.

If you are ever thinking about doing this again, I *think* Prometheus (Zorro III -> PCI bridge) is now open source (or it could be made available) so you could include PCI slots on the board.

Oh, yeah, that makes more sense than my suggestion of putting PCIs on the PCB. Will this still have the PCI cards in place actually, I always wondered that, (have the brackets fit the backplane?). Is this 3,3V or does it require a mod?

IMO Prometheus is not a realistic option from driver/compatibility perspective. There are cool things happening PPC wise with the Elbox mediators!